Note: Descriptions are shown in the official language in which they were submitted.
81795773
METHOD AND APPARATUS FOR DETERMINING
TO USE X2 GATEWAY FOR X2 INTERFACE
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. provisional
application Serial
No. 61/899,022, filed November 1, 2013.
FIELD
[0002] The present disclosure relates to communication systems and to
techniques
for establishing an X2 interface.
BACKGROUND
10003] Wireless communication networks are widely deployed to provide
various
communication content such as voice, video, packet data, messaging, broadcast,
etc.
These wireless networks may be multiple-access networks capable of supporting
multiple users by sharing the available network resources. Examples of such
multiple-
access networks include Code Division Multiple Access (CDMA) networks, Time
Division Multiple Access (TDMA) networks, Frequency Division Multiple Access
(FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA
(SC-FDMA) networks.
[0004] A wireless communication network may include a number of base
stations
that can support communication for a number of mobile entities, such as, for
example,
user equipments (ITEs). A IX may communicate with a base station via the
downlink
(DI) and uplink (UL). The DL (or forward link) refers to the communication
link from
the base station to the UE, and the UL (or reverse link) refers to the
communication link
from the LIE to the base station.
[0005] The 3rd Generation Partnership Project (3GPP) Long Term
Evolution (LTE)
represents a major advance in cellular technology as an evolution of Global
System for
Mobile communications (GSM) and Universal Mobile Telecommunications System
(UNITS). The UTE physical layer (PHY) provides a highly efficient way to
convey
both data and control information between base stations, such as an evolved
Node Bs
(eNEs), and mobile entities, such as UEs.
=
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100061 In recent years, users have started to replace fixed line
broadband
communications with mobile broadband conununicatioas and have increasingly
demanded great voice quality, reliable service, and low prices, especially at
their home
or office locations. In order to provide indoor services, network operators
may deploy
different solutions. For networks with moderate traffic, operators may rely on
macro
cellular base stations to transmit the signal into buildings. However, in
areas where
building penetration loss is high, it may be difficult to maintain acceptable
signal
quality, and thus other solutions are desired. New solutions are frequently
desired to
make the best of the limited radio resources such as space and spectrum. Some
of these
solutions include intelligent repeaters, remote radio heads, and small-
coverage base
stations (e.g., picocells and femtocells).
100071 The Fernto Forum, a non-profit membership organization focused on
standardization and promotion of femtocell solutions, defines femto access
points
(FAPs), also referred to as femtocell units, to be low-powered wireless access
points
that operate in licensed spectrum and are controlled by the network operator,
can be
connected with existing handsets, and use a residential digital subscriber
line (DSL) or
cable connection for backhaul. In various standards or contexts, a FAP may be
referred
to as a home node B (H.NB), hom.e e-node B (HeNB), access point base station,
etc.
SUMMARY
100081 Methods, apparatus and systems for initiating a communication
interface in a
wireless communication system are described in the detailed description, and
certain
aspects are summarized below. This summary and the following detailed
description
should be interpreted as complementary parts of an integrated disclosure,
which parts
may include redundant subject matter and/or supplemental subject matter. An
omission
in either section does not indicate priority or relative importance of any
element
described in the integrated application. Differences between the sections may
include
supplemental disclosures of alternative embodiments, additional details, or
alternative
descriptions of identical embodiments using different terminology, as should
be
apparent from the respective disclosures.
100091 In an aspect, a method for initiating a communication interface in
a wireless
communication system is provided. The method includes discovering a neighbor
node
at an access point, receiving, via a network message in response to
discovering the
neighbor node, an address indication associated with the neighbor node for
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configuration of the communication interface, and determining whether to
initiate one
of a direct communication interface or indirect communication interface for
communication with the neighbor node based on the address indication in the
received
network message. The direct communication interface may be an X2 interface and
the
indirect communication interface may be an X2 interface via an X2 gateway (X2-
GW)
serving as a proxy.
1100101 In a further aspect, the method may further include initiating the
direct
communication interface responsive to the address indication in the received
network
message indicating that the neighbor node does not support the indirect
communication
interface. Determining whether to initiate one of a direct communication
interface or
indirect communication interface may be based on a configuration of the access
point
and the support of the indirect communication interface based on the address
indication
comprising an address or a special value associated with the X2-GW of the
neighbor
node in the received network message.
100111 In addition, determining whether to use the direct communication
interface
or the indirect communication interface is further based on at least one of
support for
the direct communication interface, support for the indirect communication
interface, an
operations, administration, maintenance (OAM) configuration, an identity of
the
neighbor node including a physical cell identifier (PCI), enhanced cell global
identifier
(eCGI), or closed subscriber group (CSG) identity, in which the determining
may be
further based on the address indication from. the target. Further, the method
may
provide for initiating the direct or indirect communication interface based on
the
aforementioned determination.
100121 In yet further aspects, the method may provide for, after
discovering the
neighbor node at the access point, initiating transport network layer (TNL)
address
discovery by sending a TNL address request to the neighbor node, in which the
receiving the network message is in response to initiating the TNL address
discovery.
The network message may be a self-organizing network (SON) configuration
transfer
message comprising the address indication associated with the neighbor node.
100131 In related aspects, a wireless communications apparatus may be
provided for
performing any of the methods and aspects of the methods summarized above. An
apparatus may include, for example, a processor coupled to a memory, wherein
the
memory holds instructions for execution by the processor to cause the
apparatus to
perform operations as described above. Certain aspects of such apparatus
(e.g.,
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hardware aspects) may be exemplified by equipment such as mobile entities or
base stations
of various types used for wireless communications. Similarly, an article of
manufacture may
be provided, including a non-transitory computer-readable medium holding
encoded
instructions, which when executed by a processor, cause a wireless
communications apparatus
to perform the methods and aspects of the methods as summarized above.
10013a1 According to one aspect of the present invention, there is provided a
method for
initiating a communication interface in a wireless communication system, the
method
comprising: discovering a neighbor node at an access point; receiving, based
on discovering
the neighbor node, a network message that includes an address indication,
associated with the
neighbor node, for configuration of the communication interface; and
determining whether to
initiate one of a direct communication interface or an indirect communication
interface for
communication with the neighbor node based on the address indication and based
on at least
one of: support for the direct communication interface, support for the
indirect communication
interface, an operation, administration, maintenance (OAM) configuration, an
identity of the
neighbor node including a physical cell identifier (PCI), or a closed
subscriber group (CSG)
identity.
[0013b] According to another aspect of the present invention, there is
provided an apparatus
for initiating a communication interface in a wireless communication system,
the apparatus
comprising: means for discovering a neighbor node at the apparatus; means for
receiving,
based on discovering the neighbor node, a network message that includes an
address
indication, associated with the neighbor node, for configuration of the
communication
interface; and means for determining whether to initiate one of a direct
communication
interface or an indirect communication interface for communication with the
neighbor node
based on the address indication and based on at least one of: support for the
direct
communication interface, support for the indirect communication interface, an
operation,
administration, maintenance (OAM) configuration, an identity of the neighbor
node including
a physical cell identifier (PCI), or a closed subscriber group (CSG) identity.
10013c] According to still another aspect of the present invention, there is
provided an
apparatus for initiating a communication interface in a wireless communication
system, the
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apparatus comprising: at least one processor configured to discover a neighbor
node at the
apparatus; at least one transceiver configured to receive, based on
discovering the neighbor
node, a network message that includes an address indication, associated with
the neighbor
node, for configuration of the communication interface, wherein the at least
one processor is
further configured to: determine whether to initiate one of a direct
communication interface or
an indirect communication interface for communication with the neighbor node
based on the
address indication and based on at least one of: support for the direct
communication
interface, support for the indirect communication interface, an operation,
administration,
maintenance (0AM) configuration, an identity of the neighbor node including a
physical cell
identifier (PCI), or a closed subscriber group (CSG) identity; and a memory
coupled to the at
least one processor.
[0013d] According to yet another aspect of the present invention, there is
provided a non-
transitory computer-readable medium storing instructions, the instructions
comprising: one or
more instructions that, when executed by at least one computer, cause the at
least one
computer to: discover a neighbor node at an access point; receive, based on
discovering the
neighbor node, a network message that includes an address indication,
associated with the
neighbor node, for configuration of a communication interface; and determine
whether to
initiate one of a direct communication interface or an indirect communication
interface for
communication with the neighbor node based on the address indication and based
on at least
one of: support for the direct communication interface, support for the
indirect communication
interface, an operation, administration, maintenance (OAM) configuration, an
identity of the
neighbor node including a physical cell identifier (PC1), or a closed
subscriber group (CSG)
identity.
[0014] All of the operations of the foregoing methods may be performed by a
network
entity or entities of a wireless communication system(s), using components as
described in
more detail elsewhere herein
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a block diagram conceptually illustrating an example of a
telecommunications system.
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[0016] FIG. 2 is a block diagram conceptually illustrating an example of a
down link
frame structure in a telecommunications system.
[0017] FIG. 3 is a block diagram conceptually illustrating a design of a base
station/eNB and a UE.
[0018] FIG. 4 is a block diagram illustrating another example communication
system.
[0019] FIG. 5 is a block diagram of yet another example communication system.
[0020] FIG. 6 is a call flow diagram illustrating X2 communication interface
initiation
between (1-I)eNBs.
[0021] FIG. 7 illustrates an exemplary methodology for X2 interface initiation
for a source
node.
[0022] FIG. 8 illustrates an exemplary methodology for X2 interface initiation
for a target
node.
[0023] FIG. 9 shows an embodiment of an apparatus for X2 interface initiation,
in
accordance with the methodology of FIG. 7.
[0024] FIG. 10 shows an. embodiment of an apparatus for X2 interface
initiation, in
accordance with the methodology of FIG. 8.
DETAILED DESCRIPTION
[0025] The detailed description set forth below, in connection with the
appended drawings,
is intended as a description of various configurations and is not intended to
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represent the only configurations in which the concepts described herein may
be
practiced. The detailed description includes specific details for the purpose
of providing
a thorough understanding of the various concepts. However, it will be apparent
to those
skilled in the art that these concepts may be practiced without these specific
details. In
some instances, well-known structures and components are shown in block
diagram
form in order to avoid obscuring such concepts.
100261 The techniques described herein may be used for various wireless
communication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA. and
other networks. The terms "network" and "system" are often used
interchangeably. A
CDMA network may implement a radio technology such as Universal Terrestrial
Radio
Access (UTRA), cdma2000, etc. UTRA includes Widcband CDMA (WCDMA) and
other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A
TDMA network may implement a radio technology such as Global System for Mobile
Communications (GSM). An OFDMA network may implement a radio technology
such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-
Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA
are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term
Evolution (LTE) and LIE-Advanced (LIE-A) are new releases of UMTS that use E-
UTRA. UTRA, E-UTRA, UNITS, LIE, LTE-A and GSM are described in documents
from an organization named "3rd Generation Partnership Project" (3GPP).
CDMA2000
and UMB are described in documents from an organization named "3rd Generation
Partnership Project 2" (3CIPP2). The techniques described herein may be used
for the
wireless networks and radio technologies mentioned above as well as other
wireless
networks and radio technologies. For clarity, certain aspects of the
techniques are
described below for LTE, and LTE terminology is used in much of the
description
below.
100271 FIG. 1 shows a wireless communication network 100, which may be an
LIE
network. The wireless network: 100 may include a number of eNBs 110 and other
network entities. An eNB may be a station that communicates with the UE.s and
may
also be referred to as a base station, a Node B, an access point, or other
term. Each eNB
110a, 110b, 110c may provide communication coverage for a particular
geographic
area. In 3GPP, the term "cell" can refer to a coverage area of an eNB and/or
an eNB
subsystem serving this coverage area, depending on the context in which the
term is
used.
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100281 An eNB may provide communication coverage for a macro cell, a pico
cell,
a femto cell, and/or other types of cell. A macro cell may cover a relatively
large
geographic area (e.g., several kilometers in radius) and may allow
unrestricted access by
UEs with service subscription. A pico cell may cover a relatively small
geographic area
and may allow unrestricted access by UEs with service subscription. A femto
cell may
cover a relatively small geographic area (e.g., a home) and may allow
restricted access
by UEs having association with the femto cell (e.g., UEs in a Closed
Subscriber Group
(CSC), UEs for users in the home, etc.). An eNB for a macro cell may be
referred to as
a macro eNB. An eNB for a pico cell may be referred to as a pico eNB. An eNB
for a
feint cell may be referred to as a feint eNB or a home eNB (HNB). In the
example
shown in. FIG. 1, the eNBs 11.0a, 110b and 110c may be macro eNBs for the
macro cells
102a, 102b and 102c, respectively. The eNB 110x may be a pico eNB for a pico
cell
102x. The eNBs 110y and 110z may be femto eNBs for the femto cells 102y and
102z,
respectively. An eNB may support one or multiple (e.g., three) cells.
100291 The wireless network 100 may also include relay stations 110r. A
relay
station is a station that receives a transmission of data and/or other
information from an
upstream station (e.g., an eNB or a UE) and sends a transmission of the data
and/or
other information to a downstream station (e.g., a UE or an eNB). A relay
station may
also be a UE that relays transmissions for other UEs. In the example shown in
FIG. 1, a
relay station 110r may communicate with the eNB 110a and a UE 120r in order to
facilitate communication between the eNB 110a and the UE 120r. A relay station
may
also be referred to as a relay eNB, a relay, etc.
100301 The wireless network 100 may be a heterogeneous network that
includes
eNBs of different types, e.g., macro eNBs, pico eNBs, femto eNBs, relays, etc.
These
different types of eNBs may have different transmit power levels, different
coverage
areas, and different impact on interference in the wireless network 100. For
example,
macro eNBs may have a high transmit power level (e.g., 20 Watts) whereas pico
eNBs,
femto eNBs and relays may have a lower transmit power level (e.g., 1 Watt).
100311 The wireless network 100 may support synchronous or asynchronous
operation. For synchronous operation, the eNBs may have similar frame timing,
and
transmissions from different eNBs may be approximately aligned in time. For
asynchronous operation, the eNBs may have different frame timing, and
transmissions
from different eNBs may not be aligned in time. The techniques described
herein may
be used for both synchronous and asynchronous operation.
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100321 A network controller 130 may couple to a set of eNBs and provide
coordination and control for these eNBs. The network controller 130 may
communicate
with the eNBs 110 via a backhaul. The eNBs 110 may also communicate with one
another, e.g., directly or indirectly via wireless or wireline backhaul.
100331 The UFA 120 may be dispersed throughout the wireless network 100,
and
each UE may be stationary or mobile. A UE may also be referred to as a
terminal, a
mobile station, a subscriber unit, a station, etc. A UE may be a cellular
phone, a
personal digital assistant (PDA), a wireless modem, a wireless communication
device, a
handheld device, a laptop computer, a cordless phone, a wireless local loop
(WLL)
station, or other mobile entities. A UE may be able to communicate with macro
eNBs,
pico eNBs, femto eNBs, relays, or other network entities. In FIG. 1, a solid
line with
double arrows indicates desired transmissions between a UE and a serving eNB,
which
is an eNB designated to serve the UE on the downlink and/or uplink. A dashed
line
with double arrows indicates interfering transmissions between a UE and an
eNB.
100341 LIE utilizes orthogonal frequency division multiplexing (OFDM) on
the
downlink and single-carrier frequency division multiplexing (SC-FDM) on the
uplink.
OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal
subcarriers, which are also commonly referred to as tones, bins, etc. Each
subcarrier
may be modulated with data. In general, modulation symbols are sent in the
frequency
domain with OFDM and in the time domain with SC-FDM. The spacing between
adjacent subcarriers may be fixed, and the total. number of subcarriers (K.)
may be
dependent on the system bandwidth. For example, K may be equal to 128, 256,
512,
1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10 or 20 megahertz (MHz),
respectively. The system bandwidth may also be partitioned into subbands. For
example, a subband may cover 1.08 MHz, and there may be 1, 2, 4, 8 or 16
subbands
for system bandwidth of 1.25, 2.5, 5, 10 or 20 MM. respectively.
100351 FIG. 2 shows a down link frame structure used in LIE. The
transmission
timeline for the downlink may be partitioned into units of radio frames. Each
radio
frame, for example, frame 202, may have a predetermined duration (e.g., 10
milliseconds (ms)) and may be partitioned into 10 subframes 204 with indices
of 0
through 9. Each subframe, for example `Subframe 0' 206, may include two slots,
for
example, 'Slot 0' 208 and 'Slot 1' 210. Each radio frame may thus include 20
slots
with indices of 0 through 19. Each slot may include L symbol periods, e.g., 7
symbol
periods 212 for a normal cyclic prefix (CP), as shown in FIG. 2, or 6 symbol
periods for
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an extended cyclic prefix. The normal CP and extended CP may be referred to
herein as
different CP types. The 2L symbol periods in each subframe may be assigned
indices of
0 through 2L-1. The available time frequency resources may be partitioned into
resource blocks. Each resource block may cover N subcaniers (e.g., 12
subcarriers) in
one slot.
100361 In LTE. an eNB may send a primary synchronization signal (PSS) and
a
secondary synchronization signal (SSS) for each cell in the eNB. The primary
and
secondary synchronization signals may be sent in symbol periods 6 and 5,
respectively,
in each of subframes 0 and 5 of each radio frame with the normal cyclic
prefix, as
shown in FIG. 2. The synchronization signals may be used by UEs for cell
detection
and acquisition. Thc eNB may send a Physical Broadcast Channel (PBCH) in
symbol
periods 0 to 3 in slot 1 of subframe 0. The PBCH may carry certain system
information.
100371 The eNB may send a Physical Control Format Indicator Channel
(PCFICH)
in only a portion. of the first symbol period of each subframe, although
depicted in the
entire first symbol period 214 in FIG. 2. The PCFICH may convey the number of
symbol periods (M) used for control channels, where M may be equal to 1, 2 or
3 and
may change from subframe to subframe. M may also be equal to 4 for a small
system
bandwidth, e.g., with less than 10 resource blocks. In the example shown in
FIG. 2,
M=3. The eNB may send a Physical HARQ Indicator Channel (PHICH) and a Physical
Downlink Control Channel (PDCCH) in the first M symbol periods of each
subframe
(M=3 in FIG. 2). The PHICH may carry information to support hybrid automatic
retransmission (HARQ). The PDCCH may carry information on resource allocation
for
UEs and control information for downlink channels. Although not shown in the
first
symbol period in FIG. 2, it is understood that the PDCCH and PH1CH are also
included
in the first symbol period. Similarly, the PHICH and PDCCH are also both in
the
second and third symbol periods, although not shown that way in FIG. 2. The
eNB may
send a Physical Downlink Shared Channel (PDSCH) in the remaining symbol
periods of
each subframe. The PDSCH may carry data for UEs scheduled for data
transmission on
the downlink. The various signals and channels in LTE are described in 3GPP TS
36.211, entitled "Evolved Universal Terrestrial Radio Access (E-UTRA);
Physical
Channels and Modulation," which is publicly available.
100381 The eNB may send the PSS, SSS and PBCH in the center 1.08 MHz of
the
system bandwidth used by the eNB. The eNB may send the PCFICH and PHICH
across the entire system bandwidth in each symbol period in which these
channels arc
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sent. The eNB may send the PDCCH to groups of UEs in certain portions of the
system
bandwidth. The eNB may send the PDSCH to specific UEs in specific portions of
the
system bandwidth. The eNB may send the PSS, SSS, PBCH, PCFICH and PHICH in a
broadcast manner to all UEs, may send the PDCCH in a unicast manner to
specific UEs,
and may also send the PDSCH in a unicast manner to specific UEs.
10391 A UE may be within the coverage of multiple 6NBs. One of these
eNBs
may be selected to serve the UE. The serving eNB may be selected based on
various
criteria such as received power, path loss, signal-to-noise ratio (SNR), etc.
100401 FIG. 3 shows a block diagram of a design of a base station/eNB 110
and a
UE 120, which may be one of the base stations/eNBs and one of the UEs in FIG.
1. For
a restricted association scenario, the base station 110 may be the macro eNB
110c in
FIG. 1, and the UE 120 may be the UE 120y. The base station 110 may also be a
base
station of some other type such as an access point including a femtocell, a
picocell, etc.
The base station 110 may be equipped with antennas 334a through 334t, and the
UE 120
may be equipped with antennas 352a through 352r.
100411 At the base station 110, a transmit processor 320 may receive data
from a
data source 312 and control information from a controller/processor 340. The
control
information may be for the PBCH, PCFICH, PHICH, PDCCH, etc. The data may be
for
the PDSCH, etc. The processor 320 may process (e.g., encode and symbol map)
the
data and control information to obtain data symbols and control symbols,
respectively.
The processor 320 may also generate reference symbols, e.g., for the PSS, SSS,
and
cell-specific reference signal. A transmit (TX) multiple-input multiple-output
(MIMO)
processor 330 may perform spatial processing (e.g., preceding) on the data
symbols, the
control symbols, and/or the reference symbols, if applicable, and may provide
output
symbol streams to the modulators (MODs) 332a through 332t. Each modulator 332
may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain
an
output sample stream. Each modulator 332 may further process (e.g., convert to
analog,
amplify, filter, and upconvert) the output sample stream to obtain a downlink:
signal.
Downlink signals from modulators 332a through 332f may be transmitted via the
antennas 334a through 334t, respectively.
100421 At the UE 120, the antennas 352a through 352r may receive the
downlink
signals from the base station 110 and may provide received signals to the
demodulators
(DEMODs) 354a through 354r, respectively. Each demodulator 354 may condition
(e.g., filter, amplify, downconvert, and digitize) a respective received
signal to obtain
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input samples. Each demodulator 354 may further process the input samples
(e.g., for
OFDM, etc.) to obtain received symbols. A MIMO detector 356 may obtain
received
symbols from all the demodulators 354a through 354r, perform MIMO detection on
the
received symbols if applicable, and provide detected symbols. A receive
processor 358
may process (e.g., demodulate, deinterleave, and decode) the detected symbols,
provide
decoded data for the UE 120 to a data sink 360, and provide decoded control
information to a controller/processor 380.
100431 On the uplink, at the UE 120, a transmit processor 364 may receive
and
process data (e.g., for the PUSCH) from a data source 362 and control
information (e.g.,
for the PUCCH) from the controller/processor 380. The processor 364 may also
generate reference symbols for a reference signal. The symbols from the
transmit
processor 364 may be precoded by a TX MIMO processor 366 if applicable,
further
processed by the modulators 354a through 354r (e.g., for SC-FDM, etc.), and
transmitted to the base station 110. At the base station 110, the uplink
signals from the
UE 120 may be received by the antennas 334, processed by the demodulators 332,
detected by a MIMO detector 336 if applicable, and further processed by a
receive
processor 338 to obtain decoded data and control information sent by the HE
120. The
processor 338 may provide the decoded data to a data sink 339 and the decoded
control
information to the controller/processor 340.
100441 The controllers/processors 340 and 380 may direct the operation at
the base
station 110 and the UE 120, respectively. The processor 340 and/or other
processors
and modules at the base station 110 may perform or direct the execution of
various
processes for the techniques described herein. The processor 380 and/or other
processors and modules at the UEI20 may also perform or direct the execution
of the
functional blocks illustrated in FIGS. 4 and 5, and/or other processes for the
techniques
described herein. The memories 342 and 382 may store data and program codes
for the
base station 110 and the HE 120, respectively. A scheduler 344 may schedule
UEs for
data transmission on the downlink: and/or uplink.
100451 In one configuration, the UE 120 for wireless communication
includes
means for detecting interference from an interfering base station during a
connection
mode of the UE, means for selecting a yielded resource of the interfering base
station,
means for obtaining an error rate of a physical downlink control channel on
the yielded
resource, and means, executable in response to the error rate exceeding a
predetermined
level, for declaring a radio link failure. In one aspect, the aforementioned
means may
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be the processor(s), the controller/processor 380, the memory 382, the receive
processor
358, the MIMO detector 356, the demodulators 354a, and the antennas 352a
configured
to perform the functions recited by the aforementioned means. In another
aspect, the
aforementioned means may be a module or any apparatus configured to perform
the
functions recited by the aforementioned means.
100461 FIG. 4 is an illustration of a planned or semi-planned wireless
communication environment 400, in. accordance with various aspects.
Communication
environment 400 includes multiple access point base stations, including FAPs
410, each
of which are installed in corresponding small scale network environments.
Examples of
small scale network environments can include user residences, places of
business,
indoor/outdoor facilities 430, and so forth. The FAPs 410 can be configured to
serve
associated UEs 40 (e.g., included in a CSG associated with FAPs 410), or
optionally
alien or visitor UEs 40 (e.g., UEs that are not configured for the CSG of the
FAP 410).
Each FAP 410 is further coupled to a wide area network (WAN) (e.g., the
Internet 440)
and a mobile operator core network 450 via a DSL router, a cable modem, a
broadband
over power line connection, a satellite Internet connection, or the like.
100471 To implement wireless services via FAPs 410, an owner of the FAPs
410
subscribes to mobile service offered through the mobile operator core network
450.
Also, the UE 40 can be capable to operate in a macro cellular environment
and/or in a
residential small scale network environment, utilizing various techniques
described
herein. Thus, at least in some disclosed aspects, FAP 410 can be backward
compatible
with any suitable existing UE 40. Furthermore, in addition to the macro cell
mobile
network 455, UE 40 is served by a predetermined number of FAPs 410,
specifically
FAPs 410 that reside within a corresponding user residence(s), place(s) of
business, or
indoor/outdoor facilities 430, and cannot be in a soft handover state with the
macro cell
mobile network 455 of the mobile operator core network 450. It should be
appreciated
that although aspects described herein employ 3GPP terminology, it is to be
understood
that the aspects can also be applied to various technologies, including 3GPP
technology
(Release 99 [Re199j, ReI5, ReI6, Rd?), 3GPP2 technology (I xRTT, 1xEV-DO ReI0,
RevA, RevB), and other known and related technologies.
100481 In at least one embodiment, eNBs are typically interconnected with
other
eNBs via an interface called an "X2" interface, which may be a logical
interface (e.g., a
point to point link) that enables at least two respective eNBs to be directly
connected to
each other (e.g., in a peer-to-peer manner) that facilitates communication
with one
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another. In this regard, the X2 interface may be established between one eNB
and some
of its neighbor eNBs in order to exchange signaling information, among other
types of
information or data. An initialization of the X2 interface can commence, at a
first eNB,
with an identification of a suitable neighbor eNB followed by setting up the
transport
network layer (TM.) in an example. In some implementations, the identification
of a
neighbor may be done by configuration or by an automatic neighbor relation
function.
In a similar manner, a given HeNB may also establish a connection between.
other
HeNBs via an X2 interface to enable direct communication between one another.
Thus,
the X2 interface therefore may connect neighboring eNBs to one another or
neighboring
HeNBs to each other in a peer-to-peer manner to assist, for example, in
handover,
coordination of radio resources, load management, among other functions, etc.
In an
example, eNBs may be connected to an X2-Gateway, and HeNBs may also be
connected to the same X2-Gateway. In some situations, it may be advantageous
to have
the X2 interface(s) be able to connect eNBs with HeNBs and/or vice-versa in
accordance with embodiments described herein.
100491 FIG. 5 is a block diagram of yet another example communication
system
500, describing an X2-Gateway (X2-GW) reference architecture. An X2 interface
may
be used for direct communication between eNBs and HeNBs. FIG. 5 shows an X2-GW
505 coupled to eNBs 506, 507 and 508 and HeNBs 530, 535 and 535 via respective
X2
interfaces. As illustrated in FIG. 5, the aforementioned eNBs/HeNBs may be
connected
to other eNBs/HeNBs via "direct" X2 interfaces 511, 512, 515, 518, and 519, or
via
"indirect" X2 interfaces 510, 513, 514, 516, 517, and 520 by way of the X2-GW
505
acting as a proxy server. With the addition of the X2-GW 505, the X2 interface
may be
modified to enable the X2-GW 505 functions as further described by the
following.
The X2-GW 505 can act as a full proxy where a HeNB and eNB connect to the X2-
GW
505 using existing X2 setup and reset procedures. The IIeNBs and eNBs route X2
messages to the X2-GW 505, (e.g., based on eNB ID, TAI, e-C,'GI, CSG ID, etc.)
such
that there may be no need to exchange eNB configuration between the eNBs, and
the
cells behind the X2-GW 505 may be hidden from the source eNB. The X2-GW 505
can
also act as a routing proxy where eNB-to-HeNB or HeNB-to-HeNB X2 messages may
be routed at the X2-0W 505 based on the (H)eNB ID or cell ID (e.g., the target
and
source (II)eNB IDs may need to be added to the X2 message if needed to enable
simple
routing by the X2-GW 505). It is noted that the X2-GW 505 here refers to X2
full
proxy or X2 routing proxy as clamed. It may be noted that an error message may
need
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to be defined for the case where the X2-6W 505 does not support the eNB
ID/cell ID
for a received message.
MOM The X2-GW 505 may exist in 3GPP to help enable X2 connection
between
HeNBs and eNBs. The X2-GW 505 may act as a proxy between peer nodes such that
it
may facilitate X2 setup and route other X2 application protocol (X2AP)
connections.
100511 One issue may relate to how to determine whether to setup a direct
or
indirect X2 interface for communication between neighboring (H)eNBs. When a
(II)eNB discovers another neighbor (I1)eNB (e.g., for the first time), the
(10eNI3 may
learn the transport network layer (TNL) (e.g., IP) address of this neighbor
(H)eNB
through a self-organizing network (SON) configuration transfer procedure
through the
MME. In an embodiment, the (H)eNB may initiate a TNL address discoveiy
procedure
via a configuration transfer procedure in which the (II)eNB sends a
configuration
transfer message to the MME that then forwards this message to the neighbor
(H)eNB.
The configuration transfer message, among other types of data, may include a
request
for a TNL or IP address, a global cell identifier for the neighbor (II)eNB
and/or a
transport address for the (II)eNB, and after receiving the configuration
transfer message,
the neighbor (H)eNB sends back its TNL or IP address. For the X2-GW 505, it
may be
reasonable to expand this procedure to also report the X2-0W 505 TNT.,
address. The
term source node or simply "source" may be used for the node that initiates
the SON
configuration transfer procedure and the term target node or simply "target"
may be
used for the node that responds to the SON configuration transfer procedure.
100521 In a current design, the HeNB may be connected to a single X2-C1W
505 and
may be configured with the TNL address of this X2-GW 505. However, there may
be
no such configuration for a macro eNB, which may connect to one or multiple X2-
GW
505s.
100531 To solve the problem of determining whether to use the X2-GW 505
(e.g., in
an indirect X2 interface) or not, it is proposed that the target (H)eNB may
include the
X2-GW 505 mit_ address as part of the SON configuration transfer procedure if
the
target may use or support the X2 connection through the X2-GW 505 with the
source
(H)eNB.
100541 The target node may not include this address if the target node
may not use
the X2-GW 505 or prefers to use a direct X2 interface, for example based on
operations,
administration, maintenance (OAM) configuration and/or the source identity
(e.g.,
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physical cell identifier (PCI), enhanced cell global identifier (eCGT), closed
subscriber
group (CSG) ID/membership, etc.).
100551 If the target
node is a macro eNB, then the target may not be able to signal a
specific X2-GW address since there may be multiple X2-GWs that the target may
connect to. If the target eNB can determine the X2-GW TNL address of the
source
HeNB based on configuration, it may include this in the SON configuration
transfer to
indicate that it may connect to the source via this X2-GW. However, if the X2-
GW
TNL address for the source HeNB is not available to the target, the target may
still need
to signal to the source HeNB that this eNB is able to use a connection via the
X2-GW.
To solve this issue, a special value may be included in the X2-GW TNL address
field in
the SON configuration transfer procedure. This special value may be chosen not
to
correspond to an actual TNL address, or the eNB may include its own TNL
address.
This may allow the source HeNB to determine that this target eNB is able to
use the X2-
G W connection.
100561 The current
SON transfer configuration message may include the target TNL
address as a mandatory field. If the target (II)eNB prefers to use only the
indirect
connection, it may also put a special value in the target TNL address while
including the
X2-GW TNI: address (or the specific value in case of a macro eNB) where the
special
value indicates that the direct connection is not available.
100571 It may be
noted that the target (H)eNB may include the TNL address of an
X2-OW in the SON configuration transfer message to indicate the availability
of X2
connection via the X2-GW when the target (II)eNB is connected to the X2-GW or
when
the target (II)eNB knows that the source (II)eNB is connected to the X2-GW. In
another example, the target (H)eNB may include a special value for the X2-GW
TM.
address field in the SON configuration transfer message to indicate the
availability of
using the X2-GW where a special value may be a specific numeric value which
does not
correspond to an TM- address or where the special value may be the actual TNL
address of the target (H)eNB. In another example, the target (H)eNB may
include a
special value in the target (11)eNB TNL address to indicate that the direct X2
connection
is not available for this source eNB. The determining of whether to use the X2-
GW (for
the indirect interface) or not (for the direct interface) for an X2 connection
may be
configured by the OAM based on the identity information of the source (II)eNB,
with
the identity information including such information as PCI, or eCGI, CSG
1D/membership, etc.
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100581 It may be
noted that the source (H)eNB may determine whether to use the
X2 Connection via the X2-GW or not by combining the identity information of
the
target (H)eNB including PC1, eCG1, CSG ID/membership and the indication
received
from the target in the SON configuration transfer message for the availability
of the X2-
(3W based connection at the target. The source (H)eNB may make the selection
even if
the target node indicates a preference for one X2 interface when the target
supports both
direct and indirect X2 connections. For example, even if the target node sent
an X2-
OW TNL address indicating a preference for an indirect X2 interface, the
source node
may determine to use a direct interface overriding or ignoring the preference
of the
target node. In this case, the source node may decide to use the direct X2
interface or
indirect X2 interface even if (or alternatively, without considering whether)
the target
node supports the indirect X2 interface. The source (H)eNB may send the X2
Setup
Request to the target (H)eNB or to the X2-GW based on this determination.
100591 FIG. 6 is a
call flow diagram illustrating X2 communication interface
initiation between (H)eNBs. The example communication system in FIG. 6 may
include one or more (II)cNBs 110d-c, an X2-GW 610, and a core network 620. The
X2
interface initiation process may include one of a direct X2 interface between
(H)eNBs
or an indirect X2 interface between the (H)eNBs.
100601 In the
example of FIG. 6, the process may begin at step 650, with an (H)eNB
110d discovering a neighbor node such as (H)eNB 110e. After discovering the
neighbor node (H)eNB 110e, (H)eNB 110d may determine an address of the
neighbor
node. For example, (H)eNB 110d may initiate an TNL address discovery process
to
determine the TNL address of (H)eNB 110e. In an embodiment, as part of
initiating the
TNL address discovery process, tb.e (H)eNB 110d may send a TNI. address
request in a
message to the (H)eNB 110e. In this case, the node (H)eNB 110d sending the TNL
address request may be referred to as the source node and the destination node
(II)eNB
110e may be referred to as the target node. At steps 652A-B, (H)eNB 110d may
determine the 'MI., address of (H)eNB 110e. In an embodiment, the TM. address
discovery process may be carried out via a message to the target node (11)eNI3
110d
sent out via the core network 620. For example, the message may be a SON
configuration transfer message. The target node (H)eNB 110e may determine
whether
it desires to use a direct X2 connection or an indirect X2 connection or
interface via the
X2-GW serving as a proxy. The determination of whether to use the direct or
indirect
interface may be based on OAM configuration, the source node identity and
target node
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identity, or whether the target node (II)eNB 110e supports the direct and/or
indirect
interface.
100611 In case (H)eNB 110e determines to use the indirect interface via
the X2-GW,
(H)eNB 110e may send the TNL address of the X2-GW in the SON configuration
transfer message. If the target node (H)eNB 1.10e is a macro node, (H)eNB 110e
may
be connected to more than one X2-GW. For this case, in one example, the (H)eNB
110e may include a special value (e.g., a predetermined value that may be
known to the
source node) to indicate the target node is a macro node which supports an
interface via
the X2-GW connections. For this case, in another example, the (II)eNB 110e may
include its own TNL address in the field for the X2-GW TNL address.
100621 In case (H)eNB 110e determines to use the direct interface, (H)eNB
110d
may not send the X2-GW TNL address by not including any information in this
field or
it may send a special value (e.g., a predetermined value that may be known to
the source
node) to indicate that (H)eNB 11.0e does not support the indirect interface or
desires to
use the direct interface.
100631 At step 654, the (H)eNB 110d may determine whether to use the
direct or
indirect interface. For example, the determination may be based on the TNL
address
received in the SON configuration transfer message. In case (H)eNB 110d
determines
to use the direct interface, (H)eNB 110d may initiate the X2 interface with
(H)eNB
110e, at step 656A. In case (H)eNB 110e determines to use the indirect
interface,
(H)eNB 110d may initiate the X2 interface with (H)eNB 110e via the X2-GW 610,
at
step 656B.
100641 In accordance with one or more aspects of the embodiments
described
herein, with reference to FIG. 7, there is shown a methodology 700, operable
by a
network entity, such as, for example, a femtocell, a macrocell, a picocell, or
the like.
Specifically, method 700 describes a procedure for initiating an X2 interface
at a source
node. The method 700 may involve, at 702, discovering a neighbor node at an
access
point. The method 700 may involve, at 704, receiving, via a network message,
an
address indication associated with the neighbor node for configuration of the
communication interface. The method 700 may involve, at 706, determining
whether to
initiate one of a direct communication interface or indirect communication
interface for
communication with the neighbor node based on the address indication in the
received
network message.
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100651 With reference to FIG. 8, there is shown a methodology 800,
operable by a
network entity, such as, for example, a femtocell, a macrocell, a picocell, or
the like.
Specifically, method 800 describes a procedure for initiating an X2 interface
at a source
node. The method 800 may involve, at 802, receiving a request for an address
from a
neighbor node via a network message, the request relating to initiation of an
interface
between the neighbor node and an access point. The method 800 may involve, at
804,
determining an address indication of the access point for transmission to the
neighbor
node via the network message based on determining whether to use a direct
communication interface or indirect communication interface. The method 800
may
involve, at 806, sending the address indication to the neighbor node via a
network
message for initiating the communication interface.
100661 FIG. 9 shows an embodiment of an apparatus for initiating an X2
interface,
in accordance with the methodology of FIG. 7. With reference to FIG. 9, there
is
provided an exemplary apparatus 900 that may be configured as a network entity
(e.g., a
femtocell, a macrocell, a picocell, or the like) in a wireless network, or as
a processor or
similar device/component for use within the network entity. The apparatus 900
may
include functional blocks that can represent functions implemented by a
processor,
software, or combination thereof (e.g., firmware). For example, apparatus 900
may
include an electrical component or module 902 for discovering a neighbor node
at an
access point. The apparatus 900 may include an electrical component or module
904
for receiving via a network message an. address indication associated with the
neighbor
node for configuration of the communication interface. The apparatus 900 may
include
an electrical component or module 906 for determining whether to initiate one
of a
direct communication interface or indirect communication interface for
communication
with the neighbor node based on the address indication in the received network
message.
100671 In related aspects, the apparatus 900 may optionally include a
processor
component 910 having at least one processor, in the case of the apparatus 900
configured as a network entity (e.g., a femtocell, a macrocell, a picocell, or
the like),
rather than as a processor. The processor 910, in such case, may be in
operative
communication with the components 902-906 via a bus 952 or similar
communication
coupling. The processor 910 may effect initiation and scheduling of the
processes or
functions performed by electrical components 902-906.
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100681 In further related aspects, the apparatus 900 may include a radio
transceiver
component 914. A stand alone receiver and/or stand alone transmitter may be
used in
lieu of or in conjunction with the transceiver 914. When the apparatus 900 is
a network
entity, the apparatus 900 may also include a network interface (not shown) for
connecting to one or more core network entities. The apparatus 900 may
optionally
include a component for storing information, such as, for example, a memory
device/component 916. The computer readable medium or the memory component 956
may be operatively coupled to the other components of the apparatus 900 via
the bus
952 or the like. The memory component 916 may be adapted to store computer
readable instructions and data for effecting the processes and behavior of the
components 902-906, and subcomponents thereof, or the processor 910, or the
methods
disclosed herein. The memory component 916 may retain instructions for
executing
functions associated with the components 902-906. While shown as being
external to
the memory 916, it is to be understood that the components 902-906 can exist
within the
memory 916. It is further noted that the components in FIG. 9 may comprise
processors, electronic devices, hardware devices, electronic sub-components,
logical
circuits, memories, software codes, firmware codes, etc., or any combination
thereof.
100691 FIG. 10 shows an embodiment of an apparatus for initiating an X2
interface,
in accordance with the methodology of FIG. 8. With reference to FIG. 10, there
is
provided an exemplary apparatus 1000 that may be configured as a network
entity (e.g.,
a femtocell, a macrocell, a picocell, or the like) in a wireless network, or
as a processor
or similar device/component for use within the network entity. The apparatus
1000 may
include functional blocks that can represent functions implemented by a
processor,
software, or combination thereof (e.g., firmware). For example, apparatus 1000
may
include an electrical component or module 1002 for receiving a request for an
address
from a neighbor node via a network message, the request relating to initiation
of an
interface between the neighbor node and an access point. The apparatus 1000
may
include an electrical component or module 1004 for determining an address
indication
of the access point for transmission to the neighbor node via the network
message based
on determining whether to use a direct communication interface or indirect
communication interface. The apparatus 1000 may include an electrical
component or
module 1006 for sending the address indication to the neighbor node via a
network
message for initiating the communication interface.
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100701 In related aspects, the apparatus 1000 may optionally include a
processor
component 1010 having at least one processor, in the case of the apparatus
1000
configured as a network entity (e.g., a femtocell, a macrocell, a picocell, or
the like),
rather than as a processor. The processor 1010, in such case, may be in
operative
communication with the components 1002-1006 via a bus 1052 or similar
communication coupling. The processor 1010 may effect initiation and
scheduling of
the processes or functions performed by electrical components 1002-1006.
100711 In further related aspects, the apparatus 1000 may include a radio
transceiver
component 1014. A stand-alone receiver and/or stand-alone transmitter may be
used in
lieu of or in conjunction with the transceiver 1014. When the apparatus 1000
is a
network entity, the apparatus 1000 may also include a network interface (not
shown) for
connecting to one or more core network entities. The apparatus 1000 may
optionally
include a component for storing information, such as, for example, a memory
device/component 1016. The computer readable medium or the memory component
1056 may be operatively coupled to the other components of the apparatus 1000
via the
bus 1052 or the like. The memory component 1016 may be adapted to store
computer
readable instructions and data for effecting the processes and behavior of the
components 1002-1006, and subcomponents thereof, or the processor 1010, or the
methods disclosed herein. The memory component 1016 may retain instructions
for
executing functions associated with the components 1002-1006. While shown as
being
external to the memory 1016, it is to be understood that the components 1002-
1006 can
exist within the memory 1016. It is further noted that the components in FIG.
10 may
comprise processors, electronic devices, hardware devices, electronic sub-
components,
logical circuits, memories, software codes, firmware codes, etc., or any
combination
thereof.
100721 Those of skill in the art would understand that information and
signals may
be represented using any of a variety of different technologies and
techniques. For
example, data, instructions, commands. information, signals, bits, symbols,
and chips
that may be referenced throughout the above description may be represented by
voltages, currents, electromagnetic waves, magnetic fields or particles,
optical fields or
particles, or any combination thereof.
100731 Those of skill would further appreciate that the various
illustrative logical
blocks, modules, circuits, and algorithm steps described in connection with
the
disclosure herein may be implemented as electronic hardware, computer
software, or
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combinations of both. To clearly illustrate this interchangeability of
hardware and
software, various illustrative components, blocks, modules, circuits, and
steps have been
described above generally in terms of their functionality. Whether such
functionality is
implemented as hardware or software depends upon the particular application
and
design constraints imposed on the overall system. Skilled artisans may
implement the
described functionality in varying ways for each particular application, but
such
implementation decisions should not be interpreted as causing a departure from
the
scope of the present disclosure.
100741 The various illustrative logical blocks, modules, and circuits
described in
connection with the disclosure herein may be implemented or performed with a
general-
purpose processor, a digital signal processor (DSP), an application specific
integrated
circuit (ASIC), a field programmable gate array (FPGA) or other programmable
logic
device, discrete gate or transistor logic, discrete hardware components, or
any
combination thereof designed to perform the functions described herein.. A
general-
purpose processor may be a microprocessor, but in the alternative, the
processor may be
any conventional processor, controller, microcontroller, or state machine. A
processor
may also be implemented as a combination of computing devices, e.g., a
combination of
a DSP and a microprocessor, a plurality of microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration.
100751 The steps of a method or algorithm described in connection with
the
disclosure herein may be embodied directly in hardware, in a software module
executed
by a processor, or in a combination of the two. A software module may reside
in RAM
memory, flash memory, ROM memory, EPROM memory, EEPROM memory,
registers, hard disk, a removable disk, a CD-ROM, or any other form of storage
medium
known in the art. An exemplary storage medium is coupled to the processor such
that
the processor can read information from, and write information to, the storage
medium.
In the alternative, the storage medium may be integral to the processor. The
processor
and the storage medium may reside in an ASIC. The ASIC may reside in a user
terminal. In the alternative, the processor and the storage medium may reside
as
discrete components in a user terminal.
100761 In one or more exemplary designs, the functions described may be
implemented in hardware, software, firmware, or any combination thereof. If
implemented in software, the functions may be stored on or transmitted over as
one or
more instructions or code on a computer-readable medium. Computer-readable
media
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includes both computer storage media and communication media including any
medium
that facilitates transfer of a computer program from one place to another. A
storage
media may be any available media that can be accessed by a general purpose or
special
purpose computer. By way of example, and not limitation, such computer-
readable
media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage,
magnetic disk storage or other magnetic storage devices, or any other medium
that can
be used to carry or store desired program code means in the form of
instructions or data
structures and that can be accessed by a general-purpose or special-purpose
computer,
or a general-purpose or special-purpose processor. Also, any connection is
properly
termed a computer-readable medium. For example, if the software is transmitted
from a
website, server, or other remote source using a coaxial cable, fiber optic
cable, twisted
pair, digital subscriber line (DSL), or wireless technologies such as
infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or
wireless
technologies such as infrared, radio, and microwave are included in the
definition of
medium. Disk and disc, as used herein, includes compact disc (CD), laser disc,
optical
disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks
usually
reproduce data magnetically, while discs reproduce data optically with lasers.
Combinations of the above should also be included within the scope of computer-
readable media.
100771 The previous description of the disclosure is provided to enable
any person
skilled in the art to make or use the disclosure. Various modifications to the
disclosure
will be readily apparent to those skilled in the art, and the generic
principles defined
herein may be applied to other variations without departing from the spirit or
scope of
the disclosure. Thus, the disclosure is not intended to be limited to the
examples and
designs described herein but is to be accorded the widest scope consistent
with the
principles and novel features disclosed herein.
21
